GHSA-g9cg-prrw-2r8q: Pip/pypdf vulnerability

Q: What input and processing path are required for exploitation?

An attacker must provide a crafted PDF containing a TrueType or Type1 font whose /Widths entry has unusually large values. The issue is triggered when that entry is parsed, such as during text extraction.

Q: Which pypdf release contains the fix?

The issue is fixed in pypdf 6.18.1.

Q: What can be done if upgrading is not immediately possible?

Consider applying the changes from PR #4072 until an upgrade to the fixed release can be completed.

Published Oct 1, 2026

Updated

Impact

An attacker who uses this vulnerability can craft a PDF which leads to large memory consumption. This requires parsing the /Widths entry of a TrueType or Type1 fonts with unusually large values, for example during text extraction.

Patches

This has been fixed in pypdf==6.18.1.

Workarounds

If you cannot upgrade yet, consider applying the changes from PR #4072.

Affected Software

1 affected componentFixes available

pip/pypdf<6.18.1

6.18.1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade pip/pypdf to a version that resolves this vulnerability.
Fixed in 6.18.1
Upgrade
Upgrade pypdf to a version that resolves this vulnerability.
Fixed in 6.18.1

Event History

Oct 1, 2026

Advisory Published

via GitHub·03:06 PM

Data Sourced

via GitHub·03:06 PM

DescriptionWeaknessAffected Software

Frequently Asked Questions

What input and processing path are required for exploitation?

An attacker must provide a crafted PDF containing a TrueType or Type1 font whose /Widths entry has unusually large values. The issue is triggered when that entry is parsed, such as during text extraction.

Which pypdf release contains the fix?